A Study on the Safety and Immune Responses to the GVGH altSonflex1-2-3 Vaccine Against Shigellosis in Adults, Children, and Infants

The aim of the current clinical study was to evaluate, for the first time in humans (FTIH), the safety and immunogenicity of the altSonflex1-2-3 candidate vaccine against S. sonnei and S. flexneri serotypes 1b, 2a, and 3a. The vaccine was first administered to adults 18 to 50 years of age in Europe. Subsequently, the vaccine was administered to a shigellosis-endemic population in Africa, first to adults 18 to 50 years of age, then to children 24 to 59 months of age, and finally to infants 9 months of age. Infants also received a third vaccination. Three different doses of the vaccine \[low, medium, and high amounts of antigen\] were evaluated using an age de-escalation approach (from the least vulnerable adult population to the most vulnerable paediatric population). The results of this study allowed the selection of the most appropriate dose for further vaccine development in infants 9 months of age, which was the main target age group for this vaccine.